1 Technical Field
The present disclosure relates to a failure diagnosis apparatus that is mounted on a vehicle and records data for failure diagnosis of an internal combustion engine and, in particular, to an apparatus that diagnoses failure by which a driver feels that power of the vehicle is insufficient.
2 Description of Related Art
For an early discovery and an investigation of a cause of failure of an internal combustion engine in a vehicle such as an automobile, various methods for detecting a state where drive data is not normal (that is, abnormal) have conventionally been examined. As one example, it is disclosed in Japanese Patent Application Publication No. 2014-234113 (JP 2014-234113 A) that the drive data is sequentially obtained during a travel of the vehicle, that the obtained data is categorized by a pattern (also called a drive scene) of the drive data that is changed in time series, that a characteristic of each of the patterns is extracted, and that a criterion value for a determination on an abnormality is set on the basis of this characteristic.
More specifically, for example, such an abnormality that a vehicle speed does not normally correspond to depression of an accelerator pedal only occurs at a start-up of the vehicle. In addition, during acceleration after deceleration or the like, values of an accelerator pedal operation amount and the vehicle speed at this time are normally detected. If the abnormality is determined by using the same criterion value in such a case, the abnormality may not be detected at the start-up of the vehicle. In addition, despite a fact that both of the values of the accelerator pedal operation amount and the vehicle speed are normal during the acceleration after the deceleration or the like, an erroneous determination on the abnormality may be made.
In other words, the different criterion values are required for the determination on the abnormality in different travel scenes at the start-up of the vehicle and during the acceleration after the deceleration. For this reason, an apparatus disclosed in JP 2014-234113 A categorizes the drive data of the various drive scenes, for example, time-series data that indicates a relationship between the accelerator pedal operation amount and the vehicle speed, and sets the appropriate criterion value that corresponds to each of the patterns.